2 research outputs found
Finite size spectrum, magnon interactions and magnetization of S=1 Heisenberg spin chains
We report our density matrix renormalization-group and analytical work on S=1
antiferromagnetic Heisenberg spin chains. We study the finite size behavior
within the framework of the non-linear sigma model. We study the effect of
magnon-magnon interactions on the finite size spectrum and on the magnetization
curve close to the critical magnetic field, determine the magnon scattering
length and compare it to the prediction from the non-linear model.Comment: 28 pages, 8 figures, made substantial improvement
Thermodynamics of the bilinear-biquadratic spin one Heisenberg chain
The magnetic susceptibility and specific heat of the one-dimensional S=1
bilinear-biquadratic Heisenberg model are calculated using the transfer matrix
renormalization group. By comparing the results with the experimental data of
measured by Millet et al. (Phys. Rev. Lett. {\bf 83}, 4176
(1999)), we find that the susceptibility data of this material, after
subtracting the impurity contribution, can be quantitatively explained with
this model. The biquadratic exchange interaction in this material is found to
be ferromagnetic, i.e. with a positive coupling constant.Comment: 4 pages, 4 postscript figure